Cutter bit to be used with resilient retaining member



Dec. 17, 1963 c. B. KREKELER 3,114,537

CUTTER BIT TO BE USED WITH RESILIENT RETAINING MEMBER Original Filed May 11, 1960 FIG 5 Hag. E010. 1/2011. E612 F1615.

INVENTOR. C4400: 5 (ea 162,

EG- 14. Arroznevs.

United States Patent Ofllice 3,114,537 Patented Dec. 17, 1963 3,114,537 CUTTER BIT TO BE USED WITH RESILIENT RETAINING MEMBER Claude B. Krekeler, Hamilton County, Ohio, assignor to The Cincinnati Mine Machinery Co., Cincinnati, Ohio, a corporation of Ohio Continuation of application Ser. No. 28,289, May 11, 1960. This application Mar. 28, 1963, Ser. No. 269,840 16 Claims. (Cl. 26233) This application is a continuation of the copending application of the same inventor and bearing the same title, Serial No. 28,289, filed May 11, 1960; now abandoned, which application, in turn, is a continuation-in-part of Serial No. 728,476, filed April 14, 1958, now United States Letters Patent 2,965,365, issued December 20, 1960'.

Various forms of cutter bit and socket structures have been proposed, such as may be employed in mining machinery, where a primary object is the provision of a structure comprising a socket member perforated to accept the shank of a cutter bit or cutter bit holder, and including means whereby the shank will be held in the perforation in a proper position to withstand the strains of cutting; but where the arrangement of parts is such that the shank may be inserted in the perforation by a simple driving operation and later removed by a simple prying operation, thus eliminating the use of set screws and other devices requiring adjustment. In such structures resiliently actuated means are provided to hold the shank within the perforation and to permit its withdrawal.

It will be understood that mining machinery is subjected to excessive vibration and wear as well as to the corrosive action of acid mine waters. Complex mechanical structures comprising numerous parts thus present serious problems. The use of springs to provide resilient actuation is disadvantageous. Better results are obtained by backing the engagement means with bodies of resilient rubbery substances. In United States Letters Patent 2,965,365 referred to above, the engagement means is a rod-like member located in a hole in the socket member which extends transversely of and intersects the shank receiving perforation, end portions of the rod-like member lying beyond the perforation being embedded in the bodies of resilient substance. This provides a structure which is strong, and which minimizes the effect of iine cuttings, while being readily renewable.

These and other objects of the invention, which will be set forth later or will be apparent to one skilled in the art upon reading these specifications, are accomplished by that structure and arrangement of parts of which certain exemplary embodiments will now be described. Reference is made to the accompanying drawings wherein:

FIG. 1 is a perspective view of the preferred form of the resilient means of this invention.

FIG. 2 is a longitudinal horizontal sectional view of a socket member showing an exemplary bit in position therein.

FIG. 3 is a vertical sectional view of a socket member showing an exemplary bit in position therein.

FIG. 4 is a vertical sectional view of a socket showing an exemplary bit of another construction in position therein.

FIG. 5 is a side elevational view of one form of cutter bit advantageous for use in the invention.

FIGS. 6 to 13 are side elevational views of other forms of cutter bit.

FIG. 14 is a partial vertical sectional view showing a means for causing the engagement device to exert a stronger force on the bit shank.

FIG. 15 is an elevational view of a cutter bit having another form of means for engagement by a prying tool.

FIG. 16 is a partial end elevation of the same structure.

One preferred form of the resilient means of this invention is illustrated in FIG. 1, and consists of a metallic or other pin 1, preferably but not necessarily of hardened steel, encased in a body of resilient substance 3. In the central portion of this structure the resilient substance is cut away so as to expose the pin at one side as at 3a. In this central portion about half of the body of the resilient substance may be removed leaving the portion 3w behind the pin. Or, the central portion of the resilient substance may be removed entirely so as to free the pin. While it is preferred to form the device as shown in FIG. 1, the pin may be encased solidly in the rubbery substance, excess portions of it being later sheared away when a shank is driven into a socket member in which the resilient means is installed.

In order to prevent endwise spreading of the rubbery substance, the resilient retaining means is preferably provided with a cage. End members 4 and 5 of this cage may be disc shaped and of slightly smaller diameter than the end portions of the body of rubbery resilient substance 3. The cage has a back member 6, front members 7 and 8 and preferably inturned portions '9. The back member 6 of the cage will serve as means for preventing the rotation of the resilient retaining means.

The structure shown in FIG. 1 may readily be formed in a mold where the resilient substance is molded and hardened by polymerization against the pin. The resilient substance may be natural rubber, butadiene-styrene copolymer, butadiene acrylonitrile copolymer or chloroprene; and it may contain fillers, accelerators, vulcanizing agents and hardeners as well known in the art of making and using such rubbery substances. To gain special efiects, combinations of these rubbery substances may be employed. Excellent results have been obtained with chloroprene, such as neoprene, the rubbery substance being highly resistant to acid mine waters and oils and greases with which it may come in contact. While it is preferred to vulcanize or harden the rubbery substance against the pin so that they become permanently joined together, it is within the purview of the invention to make the parts separately and then assemble them. The mold may be so configured as to disclose the portion 1a of the steel red as will be readily understood.

A mode of use of the resilient means above described is illustrated in FIGS. 2 and 3. A socket member is shown at 10. While this socket member has been indi cated as part of a mining machine chain link, it will be understood that it could be part of a cutting head or other device on mining or other machinery, including machine tools, designed to take one or a plurality of bits, cutting tools or other operating elements having shanks.

The socket member has at least one shank-receiving perforation 11. The resilient means lies in a transverse hole 12 intersecting the shank-receiving perforation in such a way that when the resilient means is placed in the hole, the pin, at its central portion will lie at least partially within the perforation. In the preferred construction, the resilient body 3' has such a diameter that it must be compressed slightly to enter the transverse hole 12, and this will produce a sufiicient engagement to hold the resilient means in place, especially since the cutaway portion of the resilient body coincides with the dimension of the shank-receiving perforation, so that the shank of a cutter bit will help to retain the resilient means by engagement with the larger end portions of the resilient body, as will be evident from FIG. 2. Thus the resilient means is readily installed and as readily removed by a simple driving action, although it is possible to provide retaining means attached to the socket member at the ends of the resilient means, as for example a plate held on the socket member by screws or other means. It will be understood that a snug engagement of the resilient means in the hole 12 prevents the entry of cuttings and corrosive mine waters.

In FIG. 3 the bit is shown as a mining machine cutter bit having a head 13 and a shank 14. The head has a cutting point usually but not necessarily an inset of hard material such as tungsten carbide.

The shank 14- is provided with a notch 16, the lower operating surface of which is disposed slantwise as shown. The central portion of the pin engages in this notch. The bit is installed by placing the end of its shank in the socket perforation and driving the bit home, as by blows on the bit head with a suitable hammer-like means. During this installation the pin 1 will be displaced laterally against the resilience of the rubbery body 3 including those portions which lie wholly within end portions of the hole 12. It may be noted that the displacement of the pin compresses the rubbery body at one side but relieves pressure on it at the opposite side, so that the rubbery substance is free to be resiliently displaced around the pin. Thus the problem of providing spaces into which a rubbery body can expand laterally while it is being compressed longitudinally is not encountered.

When the bit shank is in place, as shown in FIG. 3, the central portion of the pin enters the notch 16. The engagement of the pin with the slantwise disposed lower operating surface of the notch exerts a downward force on the bit shank, holding it securely in the socket member. When it is desired to remove the bit, this may be done by a simple prying action, accompanied by the same displacement of the pin as has been described above. A shoulder 17 is preferably provided on the bit head, and a prying device having an end like a crow bar may be engaged with the top of the socket member and beneath the shoulder 17 for bit removal.

It has been found that in the use of knock-in, pry-out structures of the general type described above, certain structural features both of the bit and of the socket member as well as of the resilient retaining means, are of very great importance in providing a long service life. The heaviest strains of cutting are of course directed rearwardly and downwardly on the bit head; but the use of mining machinery involves excessive vibrations, and outward and forward forces are encountered also. While the bits themselves are expendable, excessive wear can occur both on the socket member and on the resilient engaging means.

For best results, the following structural features should characterize the structure of the invention:

(1) The shank of the cutting tool should have a reasonably snug fit in the perforation of the socket member. Because of the excessive vibrations involved, there will be such movement of the shank of a cutting tool in the socket perforation that, if the shank has a loose or sloppy lit in the perforation, the socket member will be subjected to fairly rapid wear, in spite of the action of the resilient retaining means. Thus the shank should fit the socket member perforation as snugly as is feasible without producing friction in insertion or removal. A clearance of a few thousandths of an inch is all that is required. While there is no precise limitation a clearance of about .002 to .008 inch will be found satisfactory, .005 in. being preferred.

(2) While the cutting tools illustrated herein are shown as having shanks which are rectangular in cross section, they may have other shapes without departing from the spirit of the invention. These cross sectional shapes may vary from circular to oval; the shanks may have longitudinal ribs either extending throughout their length or extending downwardly from the head for a portion only of the length of the shank. However, the least expensive hits are those having shanks which are rectangular in cross section as shown herein.

(3) Since a relatively snug fit of the shank in the perforation of the socket member is desirable, the rod-like member of the resilient controller preferably extends only 4. part way into the shank-receiving perforation. This is accomplished by a proper placement of the transverse hole in which the resilient retaining means lies.

(4) The primary strains of cutting are rearwardly di rected, and should be sustained by the engagement of the shank in the perforation of the socket member. Thus the upper portion of the rear surface of the shank should engage the upper portion of the rear surface of the perforation, while the lower portion of the front edge of the shank engages the lower portion of the front edge of the perforation. The strains of cutting should not be imposed directly on the rod-like engagement means of the resilient retainer to any greater extent than is unavoidable. Consequently, the rod-like member is preferably positioned in such a way :as to leave a suflicient surface 18 above it to withstand the strains of cutting. The rodlike member will normally be positioned at or below the center of the shank.

(5) It is necessary to provide a gauge determining abutment on the bit, since the action of the resilient retaining means has a downward component, and in order to withstand the downward strains of cutting. In theory, a gauge determining abutment could be provided either at the front or at the rear edge of the shank. However, due to the multi-directional forces which have been mentioned, it has been found advisable to provide means on the bit which will support the bit on the socket member effectively both at the front edge and at the rear edge of the shank. These means may take the form of a gauge determining abutment on the bit at both edges, or of gauge determining abutments extending along the sides of the bit shank substantially from the front edge to the rear edge. Abutment means may be provided on all sides of the shank. 5

(6) The lower rear edge of the cutting bit shank should be tapered or chamfered in such a way as to permit the shank to deflect the rod-like member upon insertion .of the bit. A charnfer starting inwardly of the rear bit edge a distance somewhat greater than the extent of the projection of the rod-like member into the shank-receiving perforation will be found suitable. It should have a relatively gentle slope with respect to the bit shank axis, preferably of about 15, and less than about 45.

(7) The notch which receives the rod-like engagement member of the resilient retaining means should, of course, be correctly placed; but it will be noted that it is the lower part only of the surface of the notch which coacts with the engagement member. The notch should be kept as small as possible to avoid weakening the shank; and, in general, the notch may be hook-shaped in elevational contour.

(8) It is desirable that the engagement member exert a very powerful downward force on the bit shank. At the same time, the bit must be removable by a prying action. Both of these effects may be accomplished by configuring the active surface of the notch as hereinafter set forth.

(9) In some instances it is desirable to have a portion of the rear edge of the bit shank parallel tothe shank axis between the lower rear edge chamfer and the notch.

(10) Since a rear gauge determining abutment exerts a strong wearing action on the top surface of the socket member, it is well to reinforce the socket member at this point with a hard alloy insert.

As shown in FIGS. 4 and 8, a bit having a head 19 and a shank 20 may be provided with lateral gauge determining, supporting abutments 21 and 22 on one or both sides. The bit will also have a ry-out shoulder 23.

In FIG. 5 a bit is shown having a head 24 and a shank 25. This bit may be provided with lateral supporting shoulders one of which is shown at 26 and with a rear gauging abutment 27. The pry-out shoulder is indicated at 28. i

The bit of FIG. 6 has a head 29 and a shank 30 with lateral supporting engaging shoulders one of which is shown at 31, and a front engaging abutment 32. In this event the pry-out shoulder is located at 33 at the rear of the head.

The lower end of the shank must have a surface which will deflect the rod-like engagement member. Such a surface is shown at 34- in FIG. 5 in a form which extends substantialiy up to the notch 35. in FIG. 6 the end deflecting surface is shown at 36, and there is a flat surface 37 on the shank between it and the notch 35.

In FIG. 7 there is shown a bit having a head 33 and a shank 39. This bit has lateral gauging and supporting shoulders one of which is shown at 40. It also has a front gauging abutment 4 1 and a gear gauging abutment 42. Since the bit of FIG. 7 has gauging means on all four sides of the shank, some other means must be provided to permit the bit to be pried out of the socket member. For this purpose the head of the bit may be provided with a hole 43.

A simpler and preferred form of bit is shown in FIG. 9. This bit has a head 44 and a shank 45, a front gauging abutment 46 and a rear gauging abutment 47. Above the front gauging abutment there is a notch 48 in the bit head providing a pry-out shoulder 49.

FIG. shows in effect a reversal of the parts of FIG. 9. The bit has a head 59 and a shank 51, a front gauging abutment 52. and a rear gauging abutment 53. The pry-out shoulder 54 is in this instance located above the rear gauging abutment 53.

E88. 11 and 12 illustrate forms of bits each with a head 55 and a shank 56 and each with lateral gauging ribs 57. The pry-out abutment 58 is located at the front of the bit head in FIG. 11. A pry-out abutment 5% is located at the rear of the bit head in FIG. 12.

A In FIG. 13, where like parts have been given like index numerals, the bit has been provided with front and rear pry-out shoulders 58 and 59.

FIGS. and 16 illustrate another means which may be used for engagement by a pry-out tool. The bit has a head 66 and a shank 61 with forward and rear gauging abutments 62 and 63. A pry-out shoulder 64 is formed on the side of the head by the illustrated projection which is a part of the forging.

The resilient retaining means used in connection with this invention may be made to exert a very powerful effect on the bit within quite a limited range of movement. It will be understood that the stiffness of the rubbery resilient substance may be controlled as desired. The downward force exerted by the rod-like engaging means will also depend upon the angularity of the engaged surface of the notch to the axis of the shank. In FIG. 14 a socket member is indicated at 65 having a perforation 6d; and the shank of a cutting tool is indicated at 67. This shank has a notch 68 for engagement by the pin 69 of the resilient retaining means. But the notch 68 has a first sur-- face 7 ti lying at a relatively gentle angle to the axis of the shank and an adjacent second engagement surface 71 lying at a greater angle. The proportioning of the parts is such that when the shank of the cutting tool is fully home in the socket, the pin or rod-like engagement means 69 will contact the surface 71, so as to exert a very powerful downward force on the shank. The angularity of the surface 71 will not be greater than about 45 to the axis of the shank so that the pin can be deflected through the action of the prying tool on the bit shank. Almost immediately, however, the rod-like engagement means will contact the surface '70, and less force will be required to remove the shank from the socket. The angulan'ty of the surface 70 to the shank axis may be, say, 15 to While the surfaces 79 and 71 have been illustrated as flat, angularly related surfaces in FIG. 14, both surfaces may if desired be part of a continuous curvature of the lower surface of the notch.

To minimize wear on the socket member, hard alloy 6 inserts or facings can be employed as illustrated at 72 and 73 in FIG. 3.

Modifications may be made in the invention without departing from the spirit of it. The invention having been described in certain exemplary embodiments, what is claimed as new and desired to be secured by Letters Patent is:

1. A cutter bit having a head and a shank, the shank adapted to be received within the perforation of a socket member, the cutter bit having, adjacent the union of the head and shank, gauge determining abutment means for contacting a socket member, said gauge determining abutment means being so located as to furnish support and gauging for the said cutter bit at least at the forward and rear edges of the shank, the shank of said cutter bit having a notch for receiving the engagement means of a resilient retaining member, and the lower rear comer of said shank being relieved to displace the said engagement means as the shank of said cutter bit is inserted in said socket member.

2. The structure claimed in claim 1 wherein said gauge determining abutment means comprise at least one rib extending across said shank from front to rear.

3. The structure claimed in claim 1 wherein said head is configured to provide a gauge determining abutment both at the front edge and at the rear edge of said shank.

4. The structure claimed in claim 1 in which said bit has lateral gauge determining shoulders and a gauge deter-mining abutment upon one edge of said shank, said bit also having a pry-out shoulder so located as to permit the insertion of a pry-out tool.

5. The structure claimed in claim 1 in which said head has gauge determining abutments extending across both sides and both edges of said shank.

6. The structure claimed in claim 5 in which said head carries a hole for engagement by a pry-out tool.

7. The structure claimed in claim 5 wherein said head has a laterally extending abutment means for engagement for a prying tool and located above said gauge determining abutment means.

8. A cutting tool having a head and a shank, said shank adapted to be received in a socket member, said head being configured to provide at least one gauge determining abutment serving to support said cutting tool on the upper surface of the socket member at least at the front and rear edges thereof, said shank having in its rear edge a notch to receive the engagement means of a resilient retaining member said notch having a lower operating surface, said surface having parts lying inwardly at progressively increasing angularities to the axis of said shank.

9. A cutting tool having a head and a shank, said shank having front and rear edges, abutment means on said head for determining the distance said shank Wiii extend into a shank-receiving perforation in a socket member, the rear edge of the shank having 'a notch which is substantially hook-shape in cross section, the upper surface of said notch meeting the shank rear edge at a high angle, and its lower surface meeting the shank rear edge at a substantially lesser angle, the part of the notch between said surfaces being arcuate in configuration, the depth of said notch being substantially no greater than the diameter of said arcuate configuration and being a small fraction of the distance between said front and rear edges, whereby said shank is not substantially weakened by the formation of said notch, the lower end of the rear edge of said shank having a slant-wise disposed lead-in surface for a resilient retainer.

10. A cutting tool capable of use in a socket member having a shank-receiving perforation and a resiliently acting retaining means extending within said perforation, said cutting tool having a head and a shank with front and rear edges, abutment means for determining the distance said shank will extend into the shank-receiving perforation, the rear edge of the shank having a hookshaped notch, the lower surface of said notch having an area capable of eflectively engaging a resiliently acting retaining means to hold said cutting tool in said socket member, the said lowersurface of the notch having an angularity to the shank axis suitable to permit the said effective engagement and to displace a resilient engagement means upon the exertion of an outwardly directed removal force upon said cutting tool, the upper surface of said notch having a substantially greater angularity to the shank aXis whereby to provide a greater hearing surface on the rear edge of said shank above said notch for a given position of said notch axially of said shank, the base of the notch between the said surfaces being located in a direction axially of said shank substantially closer to the juncture of the upper surface of said notch with the rear edge of said shank than to the juncture of the lower surface of said notch with said rear edge, whereby the depth of said notch is minimized for a given distance between the junctures of the upper and lower notch surfaces with the shank rear edge, and Without a diminution of the effective area of the notch lower surface, the base of the notch being arcuate in configuration to avoid a concentration of breaking stresses thereat, the lower portion of the shank rear edge being relieved so as to be capable of displacing a resiliently acting means as the shank of said cutting tool is inserted in said socket member.

11. The structure claimed in claim 10 wherein said notch is formed at about the midpoint of said shank rear edge.

12. The structure claimed in claim 10 wherein abut- ;ment means are formed on said head adjacent both the front and rear edges of the shank.

13. The structure claimed in claim 11 wherein abutment means are formed on said head adjacent both the front and rear edges of the shank.

14. The structure claimed in claim 1 wherein said hit also has a pry-out shoulder so located as to permit the insertion of a pry-out tool.

15. The structure claimed in claim 8 wherein said head also has a pry-out shoulder so located as to permit the insertion of a pry-out tool.

16. The structure claimed in claim 10 wherein said head also has a pry-out shoulder so located as to permit the insertion of a pry-out tool.

References Cited in the file of this patent UNITED STATES PATENTS UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent N00 3 11453? December 17 1963 Claude Bo Krekeler It is hereby certified that error appears in the above numbered patent requiring correction and that the said Letters Patent should read as corrected below.

Column 7, line 9, for "hearing" read bearing o Signed and sealed this 30th day of June 1964 (SEAL) Ame-st:

ERNEST W; SWIDER EDWARD J. BRENNER nawing Officer Commissioner of Patents 

1. A CUTTER BIT HAVING A HEAD AND A SHANK, THE SHANK ADAPTED TO BE RECEIVED WITHIN THE PERFORATING OF A SOCKET MEMBER, THE CUTTER BIT HAVING, ADJACENT THE UNION OF THE HEAD AND SHANK, GAUGE DETERMINING ABUTMENT MEANS FOR CONTACTING A SOCKET MEMBER, SAID GAUGE DETERMINING ABUTMENT MEANS BEING SO LOCATED AS TO FURNISH SUPPORT AND GAUGING FOR THE SAID CUTTER BIT AT LEAST AT THE FORWARD AND REAR EDGES OF THE SHANK, THE SHANK OF SAID CUTTER BIT HAVING A NOTCH FOR RECEIVING THE ENGAGEMENT MEANS OF A RESILIENT RETAINING MEMBER, AND THE LOWER REAR CORNER OF SAID SHANK BEING RELIEVED TO DISPLACE THE SAID ENGAGEMENT MEANS AS THE SHANK OF SAID CUTTER BIT IS INSERTED IN SAID SOCKET MEMBER.
 9. A CUTTING TOOL HAVING A HEAD AND A SHANK, SAID SHANK HAVING FRONT AND REAR EDGES, ABUTMENT MEANS ON SAID HEAD FOR DETERMINING THE DISTANCE SAID SHANK WILL EXTEND INTO A SHANK-RECEIVING PERFORATION IN A SOCKET MEMBER, THE REAR EDGE OF THE SHANK HAVING A NOTCH WHICH IS SUBSTANTIALLY HOOK-SHAPE IN CROSS SECTION, THE UPPER SURFACE OF SAID NOTCH MEETING THE SHANK REAR EDGE AT A HIGH ANGLE, AND ITS LOWER SURFACE MEETING THE SHANK REAR EDGE AT A SUBSTANTIALLY LESSER ANGLE, THE PART OF THE NOTCH BETWEEN SAID SURFACES BEING ARCUATE IN CONFIGURATION, THE DEPTH OF SAID NOTCH BEING SUBSTANTIALLY NO GREATER THAN THE DIAMETER OF SAID ARCUATE CONFIGURATION AND BEING A SMALL FRACTION OF THE DISTANCE BETWEEN SAID FRONT AND REAR EDGES, WHEREBY SAID SHANK IS NOT SUBSTANTIALLY WEAKENED BY THE FORMATION OF SAID NOTCH, THE LOWER END OF THE REAR EDGE OF SAID SHANK HAVING A SLANT-WISE DISPOSED LEAD-IN SURFACE FOR A RESILIENT RETAINER. 